Abstract

The electron transfer reaction between the photoinjected electrons in the nanocrystalline mesoporous sensitized films and the oxidizedelectrolyte in dye sensitized solar cells(DSSC) plays a major role on the device efficiency. In this communication we show that, although the presence of molecular aggregates on the free base porphyrinDSSC limits the device photocurrent response under illumination, they form an effective hydrophobic barrier against the oxidizedelectrolyte impeding fast back-electron transfer kinetics. Therefore, their drawback can be overcome by designing dyes with peripheral moieties that prevent the formation of the aggregates and are able to achieve efficiencies as high as 3.2% under full sun.

Received 30 January 2008Accepted 26 March 2008Published online 15 April 2008

Acknowledgments:

Financial support from the Spanish MEC is gratefully acknowledged (Consolider-Hope 0007-2007 project). M.P. and E.M.F. also thank the MEC for the Ph.D. grant and Juan de la Cierva fellowship, respectively. B.O. and E.P. also thank the EU-FP6 OrgaPVNet project for funding. P.B. and M.A.S. are grateful to the Direccion General de Investigación, Ministerio de Ciencia y Tecnología (CTQ2005-08989/BQU), Generalitat de Catalunya DURSI (2005SGR00108) and ICIQ Foundation for financial support.